Brazil has the world's highest annual area of tropical deforestation, and cattle ranching is the largest driver of deforestation in the Brazilian Amazon. Recent domestic and international market demand for beef and leather that are not linked to deforestation led the largest Brazilian meatpackers to adopt policies to reject supplies from ranches with recent deforestation. However, increased and sustained enforcement of such policies will be needed to reduce deforestation in these supply chains over the long-term. We sought to map the Brazilian cattle product supply chain to determine the proportion of the market, and of cattle production, that may be susceptible to market demands for deforestation-free supplies. Beef, leather and live animal exports are the most valuable products from the cattle industry, with export values tripling between 2001 and 2009, and with China, Russia and the U.S. as the largest importing countries. The markets for dairy and tallow (beef fat) are predominantly domestic. We find that around 40% of beef and 85% of leather production serve markets that have expressed concerns over environmental impacts of their purchases, while the clandestine market, which is not susceptible to market environmental demands, is estimated to comprise about one quarter of the Brazilian cattle slaughter. Demand for Brazilian cattle products is growing, and while market-driven efforts to reduce deforestation linked to legal slaughter have shown success, improved governance and other measures will be needed to tackle the environmental impacts of the clandestine industry.